In the garment manufacturing industry, clothing is often manufactured by cutting large, rectangular pieces of material from 100-150 yard rolls, followed by placing stacks of the cut pieces of material on a marker table for cutting. A pattern for cutting the material is then placed on top of the stack in preparation for cutting either by handknife or by an automatic cloth cutter such as a laser cutter. A computer optimizes the placement of the patterns on the cloth to maximize usage of material, and prepares a pattern to be used as a guide for cutting the material. After the material is cut, it must be bundled and carried to further processing stations where the material is folded, sewn, or subjected to further processing operations.
One particular type of folded ply encountered in the manufacture of men's suits is the coin pocket liner. Currently popular men's suits typically include a separately-formed coin pocket within the main jacket pocket to allow the wearer to carry coins or other small articles separately from other items in the pocket. In prior art methods of manufacture, material for forming the coin pocket is obtained as described above, requiring use of liner material to form a stack of generally rectangular plies for forming the coin pocket. The coin pockets are formed manually by folding each ply in a generally Z-shape, stitching or tacking the fold so that the fold does not separate during further processing, manually stacking and bundling the sewn folded plies, and transferring the plies to another processing station where the liner with coin pocket is sewn into the jacket of a garment.
Prior to the present invention, it has not been possible to efficiently automate the process of manufacturing such folded, sewn plies for various reasons. If the separate plies of material are cut and stacked in the conventional manner using a market table and pattern, the plies must be individually isolated and removed from the stack so that the material can be fed into subsequent processing equipment. Difficulties have been encountered in prior art material handling devices in that it has proven difficult to isolate and separate a single ply of material from a stack of material due to the tendency of pliable material such as cloth to adhere because of static electricity, frictional clinging, and thread entanglement.
Additional difficulties are encountered in automating the folding operation. Folding operations are only accurate when material is provided and handled in an aligned manner, which is difficult with pliable material such as cloth. Moreover, the material must be kept aligned when being fed to a sewing machine, lest the material become skewed and end up with an unacceptable stitch.
After a single ply is isolated, folded, and sewn, there still remains the problem of stacking the material so that it may be bundled for transfer to another processing station. Since folded plies such as those for use as coin pocket liners are thicker at one end than the other due to the fold, it has proven difficult to automatically stack the material due to the tendency of the stack to become higher toward the end including the fold than at the opposite end. This unevenness in stack height at opposite ends of the stack presents a problem in presenting a stacking surface for plies presented for stacking and bundling.
Some prior art stacking devices suffer from skewed, uneven stacks due to "dropping" of a ply onto the stack. This generally results from releasing the article to be stacked to fall onto the stack without positive guidance. Since pliable cloth plies are susceptible to air currents and unevenness in the stacking surface, releasing a ply to fall on to the top of a stack often results in skewed or uncentered stacking. This slows down subsequent operations since an operator or subsequent processing machine cannot be certain of picking up an edge of a ply at the same place in the stack every time.